野球における投手の「オーバースロー」の構造体系化に関する一考察

－運動技術史を基礎資料として－

抄録

 The purpose of this paper is to categorize the overhand pitch which is one of the techniques of the pitcher in baseball from a movement structure aspect，and as a document in the historical development process from the mid 1870s when baseball came in, to 2008.

 Firstly, the overhand pitch can be roughly classified into two systems: “an inclined torso system overhand pitch” and “a horizontal torso system overhand pitch”. The former has common movement techniques of that of the inclined torso toward second base, and, the inclined toward home base. On the other hand, the common movement technique of the latter is a vertical movement of the torso. This system of overhand pitch is primarily emphasized on control, especially, throwing the low ball.

 Secondly, two systems were categorized in to five types as follow. On the one hand, “an inclined torso system overhand pitch” are classified into three types. Number 1, “a movement of only inclining the torso type” which depend on the power of the incline torso movement. Number 2, “an inclined movement of the torso and a twist of the waist type” by incorporating the twist of the waist during an arm swing. And number 3, “an inclined movement of the torso and torsion return of the waist type” by a follow up movement: the twisting torso to the second base direction and a twist back to the home base direction. On the other hand, “a horizontal torso system overhand pitch” can be divided into two types. The first is “a horizontal torso movement and torsion return of the waist type” that incorporates a vertical movement of the torso and the twisting movement of the torso to the second base direction and a twist back to the home base direction. Another type of this system is “a vertical movement of the torso and a twist of the waist during an arm swing type”. With regard to this, the following movements are omitted: a torso movement that inclines toward second base, the twisting torso to the second base direction and a twist back to the home base direction. Therefore, this type of overhand pitch emphasizes movement stability.

 Thirdly, these types of overhand pitch can be divided by adding an additional standard of “the movement of limbs”: The category of “an inclined movement of the torso and torsion return of the waist type” can be divided into two types by the movement technique to make a driving force: “made by an extreme rise of the leg type”, and “made by a driving of the pivoting foot type”. The former is to make a driving force by a reaction of rising up the leg extremely high. The latter is based on the movements that drive the pitcher’s plate by pivoting the foot. Moreover, the “a horizontal torso movement and torsion return of the waist type” can be classified into two types in regard to the backswing arm movement: “backswing by straight arm type”, and “backswing by a raised elbow type”.

 To summarize, with regards to the “movement of the torso and waist”, there are two systems of which can be classified into five types. By adding an additional standard of “the movement of limbs”, it is possible to classify them in to seven types.